Introduction. Critical infrastructure, including transport and civilian infrastructure, is one of the determining factors for the stable and efficient functioning of the economy and development of the state. In this regard, in order to organize the restoration and modernization of Ukrainian infrastructure damaged as a result of Russian aggression, it is extremely important to determine the necessary amount of funding for these works, which will provide more favorable conditions for determining the sources of funding, timing and appropriate resources for their implementation. Problem Statement. A wide range of damage and destruction has been sustained by a fairly large number of transport and civilian infrastructure facilities, making it impossible to determine their exact extent. At present, generalized statistics on the scale of such losses are mostly known. Therefore, the development of methodological approaches to building approximation estimates of the required amount of funding for the restoration and modernization of Ukrainian transport and civil infrastructure is quite relevant from both a scientific and practical point of view. Purpose. To develop a mathematical model and an appropriate algorithm for calculating an approximation of the required amount of funding for the restoration and modernization of transport and civil infrastructure. To analyze the data on the extent of their destruction and damage caused by the Russian aggression. Materials and Methods. Statistical data and generalized estimates of the extent of damage and destruction of Ukraine's transport and civilian infrastructure. Expert estimates of the costs of restoring infrastructure. Methods of mathematical modeling, systematic and statistical analysis of losses to the country's economy. Results. The data on the volume of destruction and damage to the main objects of transport and civil infrastructure of Ukraine were analyzed. On the basis of the proposed approach, approximations of the amount of funding required for their restoration are calculated. Conclusion. The results of the study show that direct costs for the restoration of transport and civil infrastructure will amount to more than $ 252.2 billion, and, accordingly, indirect costs, taking into account the coefficient of 1.2 – $ 302.6 billion. Thus, in the coming years, it is necessary to ensure the implementation of modernization and restoration of Ukrainian infrastructure totaling more than $ 554.8 billion.